There is another interesting superstring field theory to consider: the (oriented) open-closed
superstring field theory. This is the one that should be derived as type II superstring field
theory on a non-trivial D-brane background but is worth constructing independently as it helps
to calculate non-perturbative effects. In fact, the one based on the formulation with extra
free field has already been constructed [1]}
and used for studying some non-perturbative effect
[2]}, [3]}, [4]}, [5]}, [6]}.
It is interesting to construct it based on the open-closed homotopy algebra (OCHA) [7]}
and study the relation to the one in the WZW-like formulation.
